A low surface energy fluoropolymer, poly-(1H,1H,2H,2H-perfluorodecylacrylate) (PPFDA), has received much attention due to its hydrophobicity and oleophobicity. Its potential applications in latent heat transfer, self-cleaning, barrier protection, and biomedicine demand suitable integration of the polymer with nanoscale features, particularly as devices shrink in size
1-3. To cater to such demands and to probe the polymer properties particularly under high loading of nanostructures as required by many of these applications, initiated chemical vapor deposition (iCVD) is utilized to enable conformal growth and tight integration of the polymer with the nanostructures. As a solvent-free approach, iCVD overcomes the issues of solution viscosity, liquid surface tension, and solvent residues with conventional solution casting, sol-gel, or blending methods. These issues have limited the loading of nanofillers to less than 15 wt% or 10 vol% in conventional liquid processing, while iCVD has been shown to enable a much higher loading, e.g. for TiO
2 nanoparticles, a loading of 82 wt% and 54 vol% can be achieved
4. As a result of such high nanoparticle loading, polymers can display unique properties and behavior compared to bulk because of the significant interactions between the polymer and nanoparticles at their interfaces. For example, the iCVD deposition of polyglycidol (PGL) within the mesoporous TiO
2 nanoparticle network resulted in a significant increase in the glass transition temperature of PGL compared to bulk PGL without any nanofiller, which is attributed to the hydrogen bonding interactions between PGL and surface hydroxyl groups on the TiO
2 nanoparticle surfaces
5. Here, the iCVD deposition of PPFDA in a mesoporous network of TiO
2 nanoparticles will be demonstrated. The effect of the high loading of TiO
2 nanoparticles on PPFDA properties will be discussed based on results from dynamic scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and contact angle measurements. In particular, polymer crystallinity is found to decrease appreciably. Such a decrease in crystallinity is attributed to the tortuous mesoporous TiO
2 network as well as the significant interfacial interactions of the polymer, which disrupt chain alignment. The ability to alter polymer crystallinity can ultimately influence its hydrophobicity and therefore offers a potential way to control the anti-aging, drag reduction, and heat transfer properties for its various applications
5.
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